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Pasteurella multocida and Ascaridia galli are observed with high prevalences in free range
chickens in Denmark, but the impact is unknown. A study was carried out to examine the interaction
between A. galli and P. multocida in chickens and the impact on production.
Five groups, each with 20 18-week-old Lohmann Brown chickens were infected. Group 1 was
orally infected with 1000 50 embryonated A. galli eggs. Group 2 received 10 4 cfu P. multocida
intratracheally. Group 3 was infected with A. galli and subsequently with P. multocida. Group 4 was
infected with P. multocida followed by A. galli. Group 5 was the control. The study ran for 11 weeks
where clinical manifestations, weight gain and egg production were recorded. Excretion of P.
multocida was determined on individual basis and blood smears were made for differential counts. At
the end of the study pathological lesions and the number of adult worms, larvae and eggs in the faeces
were recorded.
The birds were more severely affected when infected with both pathogens compared to single
infections with A. galli or P. multocida, respectively. A lower weight gain and egg production was
observed with dual infections. A. galli infection followed by a secondary P. multocida infection
resulted in more birds with pathological lesions and continued P. multocida excretion.
In conclusion a negative interaction between A. galli and P. multocida was observed and it is
postulated that free range chickens are at higher risk of being subjected to outbreaks of fowl cholera
when they are infected with A. galli. # 2002 Elsevier Science B.V. All rights reserved. |
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